A technology for controlling of a display direction to be a direction in which a video can be easily seen by a user when a projection-type display device projects the video onto a horizontal face such as a desk has been devised.
In Patent Document 1, a technology has been disclosed in which a projection-type display device disposed on the upper side of a projection object includes an imaging unit, a user interface image capturing an operator's motion is acquired, and a display screen is controlled based on a detection result of the motion.
In addition, in Patent Document 2, a method has been disclosed in which a display device disposed on the upper side of a projection object recognizes the position and the motion of a user and the shape of a projection object and a display position, a display direction, and the like are controlled in accordance therewith.